Photo Credit: Jan Curtis, UAF, GI |
into the Atmsophere 2001 Fall AGU Meeting Presentations related
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Photo Credit: Jan Curtis, UAF, GI |
AN: SM31B-0756 TI: Substorm Dynamics as Observed by RPI and FUV on IMAGE AU: * Green, J L EM: green at mail630.gsfc.nasa.gov AF: Space Science Data Operations Office, Code 630, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States AU: Fung, S F EM: shing.fung at gsfc.nasa.gov AF: Space Science Data Operations Office, Code 630, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States AU: Benson, R F EM: u2rfb at lepvax.gsfc.nasa.gov AF: Lab for Extraterrestrial Physics, NASA Goddard Space Flight Center, AU: Frey, H U EM: hfrey at ssl.berkeley.edu AF: Space Sciences Lab, University of California, Berkeley, AU: Mende, S B EM: mende at ssl.berkeley.edu AF: Space Sciences Lab, University of California, Berkeley, AU: Burch, J L EM: jburch at swri.edu AF: Space Science and Engineering Division, Southwest Research Institute, AU: Reiff, P H EM: reiff at rice.edu AF: Department of Physics and Astronomy, Rice University, AU: Reinisch, B W EM: bodo\_reinisch at uml.edu AF: Center for Atmospheric Research, Univerity of Massachusetts Lowell, AB: The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft is well suited to make unique observations of the aurora and associated radio emissions during substorms. Simultaneous data from the Radio Plasma Imager (RPI) instrument and the Far Ultraviolet (FUV) instrument on IMAGE will be used to study auroral zone dynamics. The FUV investigation provides simultaneous views of the aurora with the Wideband Imaging Camera (WIC, N2 LBH 140-170 nm region), the Spectrographic Imager SI12 channel (imaging proton precipitation induced Doppler shifted Lyman alpha), and the SI13 channel (imaging the 135.6 nm OI and underlying LBH lines). FUV was designed to observe the location and intensity of the aurora over the entire auroral zone. In addition to radio sounding, the RPI measures the dynamic spectra of a variety of emissions associated with the aurora every few minutes. Several substorms have been selected for a detailed comparison between FUV and RPI data. FUV observations of the aurora are used during the times when IMAGE is at apogee and well-situated in the AKR emission cone. Harmonic AKR is observed on a number of passes. DE: 2704 Auroral phenomena (2407) DE: 2740 Magnetospheric configuration and dynamics DE: 2772 Plasma waves and instabilities DE: 2788 Storms and substorms DE: 2799 General or miscellaneous SC: SM MN: 2001 AGU Fall Meeting HR: 0830h
AN: SM31B-0761 TI: Two types of localized auroral UV emission on the dayside AU: * Frey, H U EM: hfrey at ssl.berkeley.edu AF: UC Berkeley, SSL, Berkeley, CA 94720 United States AU: Mende, S B EM: mende at ssl.berkeley.edu AF: UC Berkeley, SSL, Berkeley, CA 94720 United States AU: Immel, T J EM: immel at ssl.berkeley.edu AF: UC Berkeley, SSL, Berkeley, CA 94720 United States AU: Gerard, J EM: gerard at astro.ulg.ac.be AF: Universite Liege, LPAP, Liege, B-4000 Belgium AU: Hubert, B EM: benoit at astro.ulg.ac.be AF: Universite Liege, LPAP, Liege, B-4000 Belgium AU: Fuselier, S A EM: stephen.a.fuselier at lmco.com AF: LMMS, ATC, Palo Alto, CA 94304 United States AB: The FUV instrument on IMAGE frequently observes localized ultraviolet emission on the high latitude dayside, poleward of the normal auroral oval. There are two different types of these localized emissions. One is especially distinct in the observations of Doppler shifted Lyman alpha emission from proton precipitation. This type occurs during northward IMF and high solar wind dynamic pressure. We interpret this emission as the optical signature of proton precipitation into the cusp after lobe reconnection at the magnetopause. The second type of localized emission is visible in the wide-band (WIC) and oxygen (SI13) imagers, but is absent in the proton imager. This emission occurs during northward IMF but very low solar wind density and dynamic pressure. We interpret this emission as the optical signature of electron acceleration after reconnection. DE: 2704 Auroral phenomena (2407) DE: 2716 Energetic particles, precipitating DE: 2724 Magnetopause, cusp, and boundary layers DE: 2784 Solar wind/magnetosphere interactions SC: SM MN: 2001 AGU Fall Meeting
AN: SM31B-0763 TI: Dynamics of duskside proton aurora observed with the Svalbard all-sky imager and the IMAGE satellite under northward IMF condition : November 26, 2000 event AU: * Yoshida, N EM: yoshida at pat.geophys.tohoku.ac.jp AF: Department of Geophysics, Tohoku University, Aramaki-Aoba, Sendai, 980-8578 Japan AU: Fukunishi, H EM: fuku at pat.geophys.tohoku.ac.jp AF: Department of Geophysics, Tohoku University, Aramaki-Aoba, Sendai, 980-8578 Japan AU: Frey, H U EM: hfrey at SSL.Berkeley.EDU AF: Space Science Laboratory, University of California Berkeley, Centennial Drive at Grizzly Peak Road, Berkeley, CA 94720 United States AU: Mende, S B EM: mende at ssl.berkeley.edu AF: Space Science Laboratory, University of California Berkeley, Centennial Drive at Grizzly Peak Road, Berkeley, CA 94720 United States AU: Lester, M EM: mle at ion.le.ac.uk AF: Radio and Space Plasma Physics, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, United Kingdom AU: Mukai, T EM: mukai at stp.isas.ac.jp AF: The Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510 Japan AU: Smith, R W EM: roger at gi.alaska.edu AF: Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775 United States AB: Imaging of proton aurora is an excellent probe to monitor the magnetospheric dynamics. Particularly, imaging of high-latitude proton aurora enables us to investigate phenomena related to magnetospheric boundary processes. We have been operating an all-sky proton aurora imager at Longyearbyen (75.3 N invariant latitude) in Svalbard on a routine basis. In this paper, we focus on an interval 11-16 UT on November 26, 2000 when large enhancements of proton aurora occurred twice associated with the arrival of solar wind fast shocks identified by SSCs at 07:58 UT and 11:58 UT. The IMF observed by the WIND spacecraft was mostly northward (Bz = about 15 nT) during the period of 11-16 UT, except intermittent southward IMF turnings during the period of 12:22-13:18 UT and 14:50-15:08 UT. The averaged pressure, density and velocity of solar wind were 15 nPa, 20 /cc and 600 km/s, respectively. Enhancements of proton aurora in the dusk sector beginning at 11:58 T in association with SSC lasted over 40 min. Then quasi-periodic enhancements of proton aurora with a peak intensity of 300 R of Hb and a period of about 30 min occurred in the dusk sector in the following time period from 13:30 to 16:00 UT. By comparing proton aurora images obtained from the Svalbard all-sky imager and the IMAGE/FUV instrument with charged particle data obtained by DMSP and GEOTAIL spacecraft, it is suggested that these proton aurora enhancements are results of precipitation of protons with energy of about 10 keV in the boundary plasma sheet (BPS) adjacent to the dusk sector magnetopause. We also compared proton aurora images obtained at Longyearbyen with ionospheric plasma convection patterns obtained by the Super DARN network. From these data analyses, we clarify the mechanisms of these proton aurora enhancements in the dusk sector. We also discuss the injection processes of solar wind protons across the magnetopause and the heating and acceleration processes of injected protons in the magnetopause boundary region under northward IMF condition. DE: 2704 Auroral phenomena (2407) DE: 2716 Energetic particles, precipitating DE: 2724 Magnetopause, cusp, and boundary layers DE: 2740 Magnetospheric configuration and dynamics DE: 2784 Solar wind/magnetosphere interactions SC: SM MN: 2001 AGU Fall Meeting
AN: SH32B-06 TI: Predicting Energetic Proton Events from Solar Soft X-ray Temperatures and Hard X-ray Spectra AU: * Garcia, H A EM: howard.a.garcia at noaa.gov AF: Space Environment Center/NOAA, 325 Broadway, Boulder, CO 80305 United States AB: Apparently disparate phenomena of anomalous low temperature solar soft x-rays and spectrally hardening hard x-rays are empirically related to interplanetarly energetic proton events and to one another; most flares that exhibit low temperatures in soft X-rays also exhibit spectral hardening in hard X-rays. The converse, however, is not always true - some spectrally hardening flares are not low temperature in the case of some very intense soft X-ray flares although the former are nearly always associated with proton events. Anomalous low temperatures associate with proton events for nearly all moderate to large soft X-ray flares where the heliographic location on the Sun provides good connectivity with the Earth. Thus, these phenomena appear to be complementary, one being a good proton predictor for large flares and the other a good predictor for moderate sized flares. In general, however, the two phenomena appear to be manifestations of a single species of solar flare. The defining characteristics of this species of flare and how it is related to these phenomena and to the production of energetic proton events is not well know at this time, but certain inferences may be mode from theory as well as some of its other of its observed properties. DE: 2118 Energetic particles, solar DE: 7514 Energetic particles (2114) DE: 7519 Flares DE: 7554 X rays, gamma rays, and neutrinos SC: SH MN: 2001 AGU Fall Meeting
AN: SH41B-0754 TI: Two Examples of High-Energy ESP Events AU: * Lario, D EM: david.lario at jhuapl.edu AF: The Johns Hopkins Univ., Applied Physics Lab., 11100 Johns Hopkins Rd, Laurel, MD 20723-6099 United States AU: Decker, R B AF: The Johns Hopkins Univ., Applied Physics Lab., 11100 Johns Hopkins Rd, Laurel, MD 20723-6099 United States AB: Energetic Storm Particle (ESP) events are intensity increases of energetic ions associated with the passage of interplanetary shocks. Models for ESP events include those that invoke either energetic particle acceleration by interplanetary shocks or trapping by ambient structures in the shock vicinity. Typical ESP events at 1 AU have significant proton intensity increases at energies from a few tens of keV to some tens of MeV; rare are those events with increases in the >100 MeV range. We present two ESP events, the October 20, 1989 and the February 21, 1994 ESP events, whose proton intensity increases were observed at energies >500 MeV. We use solar wind and magnetic field data from the IMP-8 spacecraft and energetic particle data from the IMP-8 and GOES-7 spacecraft. Both ESP events were generated by solar events close to central meridian (S27E10 and N09W02, respectively). The October'89 ESP event was superimposed on one of the most intense solar energetic particle (SEP) events of solar cycle 22. During the February'94 ESP event, high-energy (>39 MeV) proton fluxes rose above background level just a few hours before the arrival of the shock. High-energy (>39 MeV) proton intensities in these two events differ by two orders of magnitude, being higher in October'89. The weak interplanetary shock for the October'89 ESP event, which arrived at earth ~ 28.4 hours after the progenitor solar event, was preceded by a structure ~ 0.03 AU wide with depressed magnetic field and solar wind density. By contrast, the strong interplanetary shock of the February'94 ESP event, which arrived at earth ~ 31.5 hours after the solar event, was preceded by a well-ordered solar wind. We show that (1) the February'94 ESP event is consistent with particle acceleration at the shock, and (2) the high-energy (>39 MeV) proton population for the October'89 ESP event is not a locally shock-accelerated population, but rather a particle population confined within the structure of depressed field and plasma in front of the shock. DE: 2104 Cosmic rays DE: 2114 Energetic particles, heliospheric (7514) DE: 2139 Interplanetary shocks DE: 7514 Energetic particles (2114) DE: 7807 Charged particle motion and acceleration SC: SH MN: 2001 AGU Fall Meeting
AN: SM41B-0814 TI: Sudden enhancement of solar wind dynamic pressure and dayside detached aurora AU: * Zhang, Y EM: yongliang.zhang at jhuapl.edu AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States AU: Paxton, L EM: larry.paxton at jhuapl.edu AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States AU: Immel, T EM: immel at ssl.berkeley.edu AF: Space Science Laboratory, University of California, Berkeley, CA 94720 United States AB: Dayside detached auroras (DDA) refer to auroras observed at sub-auroral latitudes (down to 60 degree of magnetic latitude) on the dayside. They were detected by the FUV instruments on-board the IMAGE satellite [Fuselier et al., 2000, 2001; Burch et al., 2001]. The occurrence of these DDA seem to be correlated with sudden solar wind dynamic pressure enhancements. In this paper we show that, based on IMAGE FUV data, DDA are usually short lived with lifetime of a few minutes and their MLT location depends on IMF By. We find that DDA are best observed in IMAGE FUV SI-12 (Doppler red shifted Lyman Alpha line) images. This indicates that energetic proton precipitation is the major source of DDA. We also observe a sudden brightening in the dayside and nightside auroral oval associated with DDA. We find that there are two kinds of DDA, according to their development history: (1) isolated from the auroral oval during their lifetime, (2) split from the dayside auroral oval. In this presentation we will show a few examples from IMAGE to illustrate basic characteristics of DDA. We will also discuss possible mechanisms that lead to the production of the DDA, including loss cone instability, adiabatic compression, and impulsive penetration of the solar wind plasma.\ References\Burch, J., et al., EOS Trans. AGU, 82, Spring Meet. Suppl., Abstract SM21A-06, 2001.\\ Fuselier, S.A., et al., EOS Trans. AGU, 81, Fall Meet. Suppl., Abstract SM71B-03, 2000.\Fuselier, S.A., et al., Geophys. Res. Lett., 28, 1163, 2001. DE: 2139 Interplanetary shocks DE: 2704 Auroral phenomena (2407) DE: 2716 Energetic particles, precipitating DE: 2784 Solar wind/magnetosphere interactions SC: SM MN: 2001 AGU Fall Meeting
AN: SM41B-0824 TI: Occurrences of Pc 1 Waves in the Dayside Cusp, LLBL and BPS Region and Associated Enhancements of Proton Aurora AU: * Fukunishi, H EM: fuku at pat.geopgys.tohoku.ac.jp AF: Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, 980-8578 Japan AU: Kataoka, R EM: ryuho at pat.geophys.tohoku.ac.jp AF: Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, 980-8578 Japan AU: Yoshida, N EM: yoshida at pat.geophys.tohoku.ac.jp AF: Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, 980-8578 Japan AU: Lanzerotti, L J EM: ljl at bell-labs.com AF: Bell Laborastories, Lucent Technologies, Murray Hill, NJ 07974 United States AU: Engebretson, M J EM: engebret at augburg.edu AF: Physics Department, Augsburg College, Minneapolis, MN 55454 United States AU: Arnoldy, R L EM: roger.arnoldy at unh.edu AF: Spce Science Center, University of New Hampshire, Durham, NH 03824 United States AU: Mende, S B EM: mende at ssl.berkeley.edu AF: Space Science Laboratory, University of California, Berkeley, CA 94720-7450 United States AU: Frey, H U EM: hfrey at ssl.berkeley.edu AF: Space Science Laboratory, University of California, Berkeley, CA 94720-7450 United States AB: Using ULF wave data measured by search coil magnetometers installed at Automatic Geophysical Observatories (AGOs) and South Pole station in the Antarctic, the occurrence conditions of Pc 1 waves at high latitudes covering the dayside cusp, LLBL and BPS region have been investigated in detail. It is found that intense Pc 1 waves with frequencies from 0.1 to 0.6 Hz are excited in the invariant latitude range of 70 to 75 degrees by the arraival of solar wind fast shocks such as SSCs and SIs. It is also found that Pc 1 waves with frequencies from 0.1 to 0.4 Hz are excited in the localized regions of traveling convection vortices (TCVs) accompanying magnetic impulse events (MIEs). The most striking feature is that these Pc 1 waves often show falling tone spectral structures, as changing the frequencies from 0.3 - 0.4 Hz to 0.1 - 0.2 Hz over the durations of MIEs/TCVs (typically about 5 min). Since these transient Pc 1 waves are suggested to be generated by the electromagnetic ion cyclotoron (EMIC) instability, we have investigated the behaviors of protons in the dayside cusp, LLBL and BPS region using images of proton aurora obtained by the all-sky imager installed at Longyearbyen (75.3 degrees in invariant latitude), Svalbard and the FUV instrument onboard the IMAGE satellite. We have also investigated the solar wind conditions and the energy spectra of precipitating protons during Pc 1 activity using WIND, Geotail, DMSP and Akebono spacecraft. These analyses suggest that SSC/SI-related Pc 1 waves are excited by the compression of the dayside LLBL/BPS region by fast shocks, while the outward motion of the magnetopause due to the formation of hot flow anomalies (HFAs) induce ion cyclotron wave instability in the LLBL region, resulting in occurrences of MIE-related falling tone Pc 1 waves. DE: 2407 Auroral ionosphere (2704) DE: 2724 Magnetopause, cusp, and boundary layers DE: 2731 Magnetosphere--outer DE: 2752 MHD waves and instabilities DE: 2772 Plasma waves and instabilities SC: SM MN: 2001 AGU Fall Meeting
AN: SA42A-01 INVITED TI: Role of Auroral Science in Solar System Aeronomy AU: * Galand, M EM: mgaland at bu.edu AF: Center for Space Physics / Boston University, 725 Commonwealth Avenue, Boston, MA 02215 United States AU: Chakrabarti, S EM: supc at bu.edu AF: Center for Space Physics / Boston University, 725 Commonwealth Avenue, Boston, MA 02215 United States AB: Auroral science constitutes a fundamental component of geophysical research and is expanding to an increasing number of solar system bodies with improving observation capabilities and modeling tools over the last decades. For this talk we define aurora as any optical manifestation - from gamma-rays to infra-red - of the interaction of extra-atmospheric energetic electrons, ions, and neutrals with an atmosphere. The aurora is extremely valuable for remote-sensing of atmospheric constituents, of magnetic field configuration, of plasma interactions, and of energy sources. The diversity of atmospheres and plasma sources encountered in the solar system makes it ideal for comparative auroral studies. We will illustrate the variety in solar system aurorae through the example of X-ray emissions on the Earth, Jupiter, and some comets. Such an approach should lead us to further understanding of processes and interactions taking place in solar system bodies. DE: 2455 Particle precipitation DE: 5464 Remote sensing DE: 5757 Remote sensing DE: 6207 Comparative planetology SC: SA MN: 2001 AGU Fall Meeting
AN: SM42B-0845 TI: Protons trapped in the earth's magnetic field observed with the AMS experiment AU: * Fiandrini, E EM: emanuele.fiandrini at pg.infn.it AF: University and INFN, Via Pascoli 2, 06100, pg Perugia Italy AU: Esposito, G EM: gennaro.esposito at pg.infn.it AF: University and INFN, Via Pascoli 2, 06100, pg Perugia Italy AB: Accurate measurements of proton fluxes at rigidities above 400 MeV have been performed by the AMS instrument at altitudes of 370-390 Km and in the latitude interval +/-51.7 deg. We present an analysis of the AMS data, focussed on the study of the magnetically trapped component of these fluxes. The flux maps as a function of the magnetic variables (L,alpha0) are determined in the interval (0.95<L<3), (0<alpha0<90) for protons with R<10 GV. The results are compared with existing data at lower energies and in similar (L,alpha0) range. DE: 2799 General or miscellaneous SC: SM MN: 2001 AGU Fall Meeting
AN: SM42D-03 TI: Simultaneous Observation of Magnetospheric Neutral Atoms and Proton Aurora AU: * Mende, S B EM: mende at ssl.berkeley.edu AF: Space Sciences Laboratory, University of California, Centennial Drive at Grizzly Peak Blvd., Berkeley, CA 94720 United States AU: Frey, H U AF: Space Sciences Laboratory, University of California, Centennial Drive at Grizzly Peak Blvd., Berkeley, CA 94720 United States AU: Immel, T J AF: Space Sciences Laboratory, University of California, Centennial Drive at Grizzly Peak Blvd., Berkeley, CA 94720 United States AU: Mitchell, D G AF: The Johns Hopkins University, Johns Hopkins Road, Laurel, MD 20723 United States AU: Brandt, C AF: The Johns Hopkins University, Johns Hopkins Road, Laurel, MD 20723 United States AU: Gerard, J AF: University of Liege, 5 Ave Cointe, Liege, B-4000 Belgium AB: Data from the High Energy Neutral Atom (ENA) and the far ultraviolet (FUV) imagers on IMAGE were compared for a six hour period during which a reasonably intense substorm occurred. The substorm presented is typical of a substorm expansive phase showing that while the total electron precipitation suddenly increase one whole order of magnitude, the protons increase only about 50\%. In principle ENA images represent the trapped fluxes in the magnetosphere while the proton aurora measured by the FUV SI12 instrument represents the precipitating component. At substorm onset the increase in intensity of the auroral protons and electrons is very sudden while the intensification of the ENA-s coming from regions of L<6 is much more gradual. The intensification of the precipitating electrons is relatively short lived (~ 10 minutes) while the ENA enhancements are long lived (almost a whole hour). Just prior to the substorm expansive phase (in the growth phase) the precipitated proton and electron fluxes encounter a minimum while the ENA-s show a slight growth. DE: 2704 Auroral phenomena (2407) DE: 2716 Energetic particles, precipitating DE: 2720 Energetic particles, trapped DE: 2740 Magnetospheric configuration and dynamics DE: 2788 Storms and substorms SC: SM MN: 2001 AGU Fall Meeting
AN: SM52B-01 TI: Signatures of Pseudo-breakup, Breakup of a Full Substorm Onset, and Poleward Border Intensifications Compared. AU: * Voronkov, I EM: igor at space.ualberta.ca AF: University of Alberta, Department of Physics, University of Alberta, Edmonton, Ab T6G 2J1 Canada AU: Donovan, E F EM: eric at phys.ucalgary.ca AF: University of Calgary, Department of Physics and Astronomy, University of Calgary, Calgary, Ab T2N 1N4 Canada AU: Samson, J C EM: samson at space.ualberta.ca AF: University of Alberta, Department of Physics, University of Alberta, Edmonton, Ab T6G 2J1 Canada AB: For several exceptional events, we use ground-based and in-situ data to compare the ionospheric, geostationary, and mid-tail signatures of the pseudo-breakup, breakup, and poleward border intensifications (PBIs). In doing so, we utilize CANOPUS magnetometer and multi-wavelength photometer and All-sky imager data, as well as field measurements provided by the GOES 8, GOES 9, and Geotail spacecraft. We have identified a set of distinguishable signatures of each process. Pseudo-breakup consists of two distinct stages: near-linear arc intensification corresponding to the ``explosive growth phase" at geostationary orbit, and poleward vortex expansion that starts simultaneously with explosive onset of short period pulsations (Pi1, Pi2) and dipolarization observed at geostationary orbit. It can be accompanied by local perturbations of the equatorward part of the electron precipitation region and by formation of the substorm-like local current system but neither by optical signatures of the lobe flux reconnection nor by perturbations in the mid-tail. It typically saturates near the equatorward border of the electron precipitation region producing a mushroom-like auroral structure. Breakup starts with the same two-stage initial scenario of the arc intensification and vortex evolution but it rapidly expands poleward and is accompanied by optical signatures of reconnection onset, namely the aurora develops into a cell-like structure of the size compatible with the whole auroral zone width. This occurs at the time when mid-tail disruption signatures are observed. Full onset launches a second, more global, larger Pi2 burst. Finally, we show an example of PBIs observed as long period pulses of electron precipitation at the poleward border of auroral region, followed by the high-latitude proton aurora. The commencement of PBI coincided with bursty bulk flows and pulses of plasma energization in the mid-tail. Observed features are discussed with respect to recent ideas claiming that we are dealing with processes (breakup, full onset, and PBI) of distinct physical nature that require different conditions and thresholds for their commencement. DE: 2704 Auroral phenomena (2407) DE: 2708 Current systems (2409) DE: 2764 Plasma sheet SC: SM MN: 2001 AGU Fall Meeting u Related Websites If you have any questions or comments regarding this webpage, feel free to contact: - Marina Galand (mgaland at bu.edu). |